Phalloidin Staining for F-Actin in Hepatic Stellate Cells

Explorative 3-D culture of early secondary follicles in a time lapse system for up to 36 days gives valuable, but limited insights in follicular development

BACKGROUND

Cryopreservation of ovarian cortical tissue is an important option for female fertility preservation. This is particularly valuable for cancer patients who need to be treated urgently with chemotherapy, leaving no time for hormonal stimulation. The transfer of malignant cells in certain cancers remains as a potential risk after freezing, thawing and transplantation of ovarian tissue while isolation and in vitro growth (IVG) of follicles could be a safe alternate approach of female fertility protection.

METHODS

Ovarian cortex tissue was frozen, thawed and cultured for 8 days prior to isolating and embedding of early secondary follicles in a 3D matrix, suitable for time lapse monitoring for up to 36 days. Continuous growth of a theca-like cell layer and extrafollicular protrusions were visually evaluated with a permanent monitoring system facilitating real-time follicular development without deviations in the culture conditions. Occurrence of theca cell growth was visually characterized by extrafollicular formation of cells, beyond the outer follicle boundaries. To validate the results observed by time-lapse monitoring, live cell imaging was conducted and determined with immunofluorescence staining.

RESULTS

Individual follicles significantly increased in size over time. Time-lapse video monitoring revealed extending and retracting of filopodia-like structures in the outer follicular region adjacent to the 3D environment. Theca-like cells and actin components of filopodia-like structures were identified based on immunofluorescence staining.

CONCLUSIONS

Time lapse monitoring of 3-D cultured follicles is a promising explorative approach to obtain valuable visual insights regarding the many facets of follicular growth and to optimize follicular culture conditions towards a clinical application. As the study is limited by a lack of mechanistic insights into theca cell differentiation and filopodia function, additional studies are necessary to validate the preliminary results of this approach.

Genetic and Molecular Characterization of H9c2 Rat Myoblast Cell Line

This study presents a comprehensive genetic characterization of the H9c2 cell line, a widely used model for cardiac myoblast research. We established a short tandem repeat (STR) profile for H9c2 that is useful to confirm the identity and stability of the cell line. Additionally, we prepared H9c2 metaphase chromosomes and performed karyotyping and molecular cytogenetics to further investigate chromosomal characteristics. The genetic analysis showed that H9c2 cells exhibit chromosomal instability, which may impact experimental reproducibility and data interpretation. Next-generation sequencing (NGS) was performed to analyze the transcriptome, revealing gene expression patterns relevant to cardiac biology. Western blot analysis further validated the expression levels of selected cardiac genes identified through NGS. Additionally, Phalloidin staining was used to visualize cytoskeletal organization, highlighting the morphological features of these cardiac myoblasts. Our findings collectively support that H9c2 cells are a reliable model for studying cardiac myoblast biology, despite some genetic alterations identified resembling sarcoma cells. The list of genes identified through NGS analysis, coupled with our comprehensive genetic analysis, will serve as a valuable resource for future studies utilizing this cell line in cardiovascular medicine.

Genetic Characteristics of the Rat Fibroblast Cell Line Rat-1

The Rat-1 cell line was established as a subclone of the parental rat fibroblastoid line F2408, derived from Fisher 344 rat embryos. Rat-1 cells are widely used in various research fields, especially in cancer biology, to study the effects of oncogenes on cell proliferation. They are also crucial for investigating signal transduction pathways and play a key role in drug testing and pharmacological studies due to their rapid proliferation. Therefore, Rat-1 cells are an indispensable research tool. While some cytogenetic information on their basic chromosomal features is available, detailed genomic analyses, such as karyotype analysis, short tandem repeat (STR) profiling, and whole-genome sequencing, have not been thoroughly conducted. As a result, the genetic stability and potential variations in Rat-1 cells over extended culture periods are poorly understood. This lack of comprehensive genetic characterization can limit the interpretation of experimental results and requires caution when generalizing findings from studies using this cell line. In this study, we describe the genetic characterization of the Rat-1 cell line. We established a karyotype, performed multicolor fluorescence in situ hybridization (mFISH), identified chromosomal losses and gains, and defined an STR profile for Rat-1 with 31 species-specific markers. Interestingly, the chromosomal imbalances found in Rat-1 cells resemble those found in human epithelioid sarcoma or liposarcoma. Additionally, we analyzed the transcriptome of Rat-1 cells through mRNA sequencing (mRNA-Seq) using next-generation sequencing (NGS). Finally, typical features of these fibroblastic cells were determined using electron microscopy, Western blotting, and fluorescent phalloidin conjugates.

Fustin suppressed melanoma cell growth via cAMP/PKA-dependent mechanism

Melanoma, a cancer arising from melanocytes, requires a novel treatment strategy because of the ineffectiveness of conventional therapies in certain patients. Fustin is a flavanonol found in young fustic (Cotinus coggygria). However, little is known about its antimelanoma effects. Our study demonstrates that fustin suppresses the growth of B16 melanoma cells. Phalloidin staining of cytoskeletal actin revealed that fustin induced a conformational change in the actin structure of melanoma cells, accompanied by suppressed phosphorylation of myosin regulatory light chain 2 (MLC2), a regulator of actin structure. Furthermore, the protein kinase A (cAMP-dependent protein kinase) inhibitor H89 completely attenuated fustin-induced downregulation of phosphorylated myosin phosphatase targeting subunit 1, which is involved in dephosphorylation of MLC2. In a mouse model, administration of fustin suppressed tumor growth in B16 melanoma cells without adverse effects. In conclusion, our findings suggest that fustin effectively suppresses melanoma cell growth both in vitro and in vivo.

Novel Screening System for Biliary Excretion of Drugs Using Human Cholangiocyte Organoid Monolayers with Directional Drug Transport

It has recently been reported that cholangiocyte organoids can be established from primary human hepatocytes. The purpose of this study was to culture the organoids in monolayers on inserts to investigate the biliary excretory capacity of drugs. Cholangiocyte organoids prepared from hepatocytes had significantly higher mRNA expression of CK19, a bile duct epithelial marker, compared to hepatocytes. The organoids also expressed mRNA for efflux transporters involved in biliary excretion of drugs, P-glycoprotein (P-gp), multidrug resistance-associated protein 2 (MRP2), and breast cancer resistance protein (BCRP). The subcellular localization of each protein was observed. These results suggest that the membrane-cultured cholangiocyte organoids are oriented with the upper side being the apical membrane side (A side, bile duct lumen side) and the lower side being the basolateral membrane side (B side, hepatocyte side), and that each efflux transporter is localized to the apical membrane side. Transport studies showed that the permeation rate from the B side to the A side was faster than from the A side to the B side for the substrates of each efflux transporter, but this directionality disappeared in the presence of inhibitor of each transporter. In conclusion, the cholangiocyte organoid monolayer system has the potential to quantitatively evaluate the biliary excretion of drugs. The results of the present study represent an unprecedented system using human cholangiocyte organoids, which may be useful as a screening model to directly quantify the contribution of biliary excretion to the clearance of drugs.